Reverse engineer small circuit board

Projects General Guidance
1

I have a small circuit board that I would like to reverse engineer using an ardunio (probably using just the ATmega chip with the boot loader). The circuit board interfaces to a a capacitance sensor, a hall magnetic sensor and a roller ball switch (used to determine if the circuit board has been rotated 90 degrees vertical).

I think I have the have the programming done but I really need to minimize the power consumption. The existing device has 4 CR2777 cells in series and the device barely lasts 5-6 months. Basically the device is activated when the roller switch status changes and the device stays active for about 20sec. During the 20 secs, there are a couple of LEDs that illuminate to give a status.. When in use, the device is activated about 30 times per day and over the 5-6 months, the device is used about 40 days.

I have read many of the arduino posts on reducing power consumption. I would like to extend the life by a factor of 2 or more.

Is this a realistic goal?

Appreciate any comments.

2

Well, how much current does the existing circuit draw when active, and more importantly (and this may be difficult to measure) how much when inactive?

3

The '328P or whatever processor can be put in power down sleep mode to save on current draw, and the other parts can have their power controlled before the processor goes to sleep.
Some thing will need to pull an interrupt pin low to wake the processor - can be time based, or some other part of the circuit that remains powered.

4

Without knowing the consumption when idle it is a shot in the dark if it can be improved.
I assume you do not run the device dry, but what quits when it runs dry - the processor or the LED's?
Today's LEDs comes in range of intensity and current when on.
Maybe worth a while to tweak the current limiting resistor if you run it from all the cells or just try to run the LED power from one cell only.